Dunnage bars are commonly employed in rail cars, semitrailers, ship holds, freight containers and the like to prevent the shifting of freight and to serve as supports for elevated floors. Such dunnage bars commonly consist of an elongated bar element having end fittings cooperating with elongated fixed tracks attached to the walls of the freight transporting vehicle. A variety of type of fittings are used to connect the bar to the tracks and a variety of locks are employed for releasably connecting the fittings to the tracks permitting adjustment of the bars relative to the track and preventing accidental release therefrom.
However, most dunnage bar fittings are fully releasable from the associated track permitting the bar to be removed from complete association with the track, and as the requirements and usage of dunnage bars varies with each freight load the dunnage bars are often removed from the vehicle or stored in such a location as to be damaged, or inadvertently or purposely discarded. As a dunnage bar, and its associated fittings is a relatively expensive apparatus the loss or damage of the bar imposes high costs upon the vehicle owner or shipper responsible for the dunnage equipment, and there has been a need for dunnage bars capable of versatile adjustment within its tracks but which cannot be lost or discarded.
It is an object of the invention to provide a dunnage bar system wherein the bar is "captive" with respect to its associated track and cannot be removed from the track, but is longitudinally adjustable thereto.
A further object of the invention is to provide a captive dunnage bar system utilizing a bar having end fittings associated with a fixed elongated track wherein the end fittings are locked within the track, but are selectively adjustable therein between predetermined locations.
Another object of the invention is to provide a captive dunnage bar system utilizing a track having spaced opposed parallel sides having openings formed therein, and defining an elongated slot of lesser dimension than the spacing between the track sides, the dunnage bar having a fitting head within the track attached to a neck extending through the slot wherein the fitting head cannot be removed through the slot and the head includes projections selectively cooperating with track openings to lock the bar fitting at predetermined locations on the track.
A further object of the invention is to provide a captive dunnage bar system utilizing dunnage bar fittings captive within an elongated track wherein rotational adjustment of the fitting relative to the track locks and releases the fitting relative to the track.
Another object of the invention is to provide a captive dunnage bar system utilizing a dunnage bar head captive within a track, the head being rotatively mounted upon a bar neck extending through a track slot, and a latch associated with the fitting head controlling the rotational position of the head to the neck.
An additional object of the invention is to provide an elongated track for a captive dunnage bar system wherein the track may be incorporated into freight vehicle walls and may serve as a structural member of the vehicle.
The configuration of the elongated track used with the dunnage bar system of the invention may take a variety of forms, but the bar must include parallel spaced opposed portions in which openings are defined. The openings within opposed portions are misaligned with respect to the track length, and the track defines a slot extending the track length which is of lesser dimension in width than the spacing between the track portions in which the openings are defined.
The dunnage bar includes fittings at each end, and the fittings include a neck extending in the direction of the bar length having an outer end upon which fitting head structure is associated. In one embodiment of the invention the fitting head is fixed relative to the bar, while in another embodiment the fitting head is rotatably associated with the bar neck.
In the embodiment wherein the fitting head is fixed relative to the bar the head is defined by flange portions lying within a plane perpendicular to the bar length extending from neck portions which project through the track slot. The fitting head includes projections capable of being received within the track openings at one rotational attitude of the bar relative to the bar length. By rotating the bar, the rotational attitude of the fitting head relative to the track changes permitting the head projections to withdraw from the track openings and permitting the fittings, and bar, to be longitudinally adjusted relative to the track.
In another embodiment of the invention, the fitting head is rotatably mounted upon the bar neck, and includes projections selectively cooperable with the track openings at a first rotational position upon the neck. At a second rotational position the fitting head projections are released from the track openings and adjustment of the fitting, and bar, relative to the track is readily accomplished. A manually operated latch formed upon the fitting neck cooperates with the head when the head is in the operative position preventing inadvertent rotation of the fitting head which would release the fitting from the desired location relative to the track.
A variety of track configurations may be used in the practice of the invention, the various configurations are illustrated wherein the track may be incorporated into the walls of the cargo space, and may serve as structural members. The track elements may include means for cooperating with the cargo space walls and such "built-in" track forms eliminate the likelihood of track damage while providing an attractive appearance within the cargo space.